The invention relates to a centrifugal separator for separating dirt particles from a liquid comprising a rotating separator cylinder arranged in a separator housing.
U.S. Pat. No. 6,572,523 discloses a centrifugal separator that is used to clean motor oil in internal combustion engines. The centrifugal separator has a fixed housing in which a rotating separator cylinder is arranged that is supported and driven by a rotor shaft. The rotor shaft lies in a cylindrical tube whose wall is permeable and enclosed by a lamellar stack of plates, between which flow spaces are formed through which the solid component in the liquid is discharged outwardly under the action of the centrifugal forces. The liquid components, however, remain in the cylindrical tube and are discharged axially.
To make it possible to determine whether the separator cylinder is rotating at the desired speed within the fixed housing, the centrifugal separator has a detection device associated with it to indicate the rotational movement of the separator cylinder. This detection device comprises a rotor sensor with a visual display unit. The sensor comprises a coil fixed to the housing and a permanent magnet attached to the separator cylinder, which regularly passes the coil with each rotation of the separator cylinder, such that a voltage is induced in the coil that periodically causes the display unit to light up. If the display unit does not light up at all, or if the frequency is too low, a monitoring operator can see this from the outside without having to take the housing apart. This enables an early detection of any faults.
Possible faults include damaged bearings, for example. However, clogging of the filter unit by dirt deposits is almost impossible to detect, because the rotor speed is maintained even if the filter unit is clogged. As a result, there is a risk that the cleaning performance continues to decrease, without it being detected from the outside.